Brake operating mechanism



June 18, 1935.

E. B WILSON BRAKE OPERATING MECHANISM Filed May 31, 1955 M/vCsA/TQR Patented June 18, 1935 BRAKE OPERATINGMECHANISM' Edward [Brian Wilson, Westminster, London, Y

England, assignor to Wilson Box ,(Fo'reign V Rights) LimitedjLondon, England Application May 31,1933,.Serial ndevsnssff I In Great Britain June 6,1932 g fir": 7 Y

i This invention relates to improvements in or in connection with gearechanging mechanism of the type wherein reaction members are'heldstationary bymeans ofbrakes." 1'

:15 1 :=In e'picyclic change spe'ed'gearing, it is notionly 15 if tensioned in the same direction.

- In-mechanism of this-type, asillustrated and described in" British patent specification No. 220,021 granted to-Walter Gordon Wilson, the brakes for the forwardgears tend to lapin the Z one'dir'ection, and as it is desirable that allthe brakes, both for *the'forward and" reverse gears,

should be actuated by a common means, a mechanism is described and illustrated in United States'P'atent N 02- 1,915,706 granted to Walter Gordon Wilson, whereby, by means of the employment of certain additional parts, lapping in the contrary direction is brought about in connection with the brake controlling the reaction drum for the reverse gear.

" The object of the present invention is to provide a simpler means, whereby the strap for holding the reaction drum for the reverse gear tends to wrap in the required direction, while the actuating means is adapted to be operated by a como 35 mon member, and at the same time no extraload is thrown upon the shafts or bearings, andthe proper selection of the desired gear is assured.

The invention consists in a brake operating mechanism for the reverse speed of an epicyclic change speed gear, comprising a pair of brake bands surrounding the brake drum and superimposed one upon the other, the ends of the inner band being disposed on the opposite side of the drum to those of the outer band, a link pivoted at one end to one end of the inner band and at its other end secured to the gear box, a pull rod secured to one end of the outer band, a finger secured at one end to the gear box and at its other end pivotally supporting the said pull rod, a toggle lever pivotally connected to the said finger and engaging the free end of the outer band, a strut pivotally connected to the said toggle lever and a rocking bus bar supporting the said strut.

55 The arrangement is such that when the bus bar is raised the free end of the outer band is ence toltheaccompany'ing drawing, in which': \35

Figure-Lie a front elevation of: the brake element'and 'itsxassociated operating mechanismrfor the reverse gear, in the off position,-

' Figure 2, a View similar to Figure 1, showing the operating mechanism inthe on position, 10.

Figure 3 a section through the brake bands taken on the line 3-3 of Figure l, and 'Figure 4, a view similar to Figure 3, showing an alternative arrangement'oi brake bands.

"Figure 5 is a side elevation of the brake.

In carrying the invention into effect, the brake element for the reversing drum comprises a brake band I which extends around the brake drum 2, and forms a secondary brake element. Super-. imposed upon-the brake band Us a band brake 3. 0 whichforms the primary brake element and is so arranged as to' contact across half itswidth with the br'ake drum, thus constituting a direct brake (see Figure 3)..- It is'to be understood that, 7 although in the preferred arrangement of the brake element only one secondary brake band i is used, two such brake bands, disposed side by side as shown in Figure 4, could be included if necessary. Each band has its own brake lining 25 of asbestos or other similar material, and is arranged so that its two ends are relatively near to one another, the respective ends of one band being displaced substantially 180 to those of the other band, so as to be on opposite sides of the centre of the drum. One end of the primary brake band 3 is provided with a block 4 pivotally connected at 5 to a toggle lever mechanism, to be hereinafter described, whilst the eye-piece 6 on theother end of the band 3 is pivotally connected at 1 to, a pull rod 8. The secondary brake band i is at tached at one end to a lug 9 which is extended radially through a slot ID in the primary brake band 3, and extends round the drum 2 following its direction of rotation, that is in a counter-= clockwise direction, and is left with a free end at a point just below the lower end of the slot ID. The lug 9 is anchored as by a, link H pivotally secured at I2 to the base plate l3 of the gear box.

The brake operating mechanism comprises the bus bar l4 fulcrumed about the knife edge IS on the bottom plate I3, which bar supports, by means of a knife edge I6, a strut I! having piv- 55 otally mounted at its upper end l8 a toggle lever I9 which is extended to form a hooked end 20 having a knife edge connection 5 with the hooked end 4 of the primary brake band 3. The other end 6 of the said band 3 is pivotally connected at I to the pull rod 8, the upper end of which rod is pivotally supported, by means of a knife edge 2 I, upon a finger 22, which latter is in turn pivotally connected at its upper end to the toggle lever l9 by a knife edge 23, and at its lower end pivotally secured at 24 to the bottom plate l3.

' may be operated by the lever andv link actuating system described and illustrated in United States Patent No. 1,854,359 granted to Walter Gordon Wilson, is allowed to swing upwardly about its fulcrum, l5 (see Figure 2) thereby imparting an upward movement to the strut H which causes the toggle lever l9 to swing in a clockwise direction about the fulcrum 23 and exert a downwardpressure on the hooked end 4 of the primary brake band 3. This downward pressure causes the primary brake band 3 to be tightened on to the brake drum 2 in the direction of rotation of the latter, viz, counterclockwise direction, the other end 6 of the band being anchored through the pull rod 8 and finger 22.

When such a braking system is relaxed, the brake bands would be free to drop and rub on the top of the drum 2. Any suitable devices may be used to prevent this; for instance, the lower part of the primary band 3 is adapted to be supportedat two points upon a pair of stops 29 each pivotally secured at and 3| to the bottom plate I! and a lug 32, respectively. These parts are so positioned that when the brake is released, the bands are kept clear equally all round or concentric with the drum.

By means of this invention, a simplified form of brake actuating mechanism is supplied which enables the wrapping efiect of the bands to occur in the appropriate directions, while the bands for holding the drums for the forward gears, as well as the reverse, are actuated by the same common member and the brake actuating mechani'sm is all on the same side of the gear box; the toggle lever fulcrum will always remain in substantially the same position relatively to the centre of the gear system when the brake is not being applied, whatever adjustment may have taken place by reason of the condition of its operative lining, and as the constant position of this point is an essential requirement for the proper functioning of the mechanism, the present invention ensures by simple means the certainty'or selection and operation of the whole system, whatever adjustment for wear may. have taken place.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:'-

Brake operating mechanism for the reverse speed. of an epicyclic change speed gear, comprising a pair of brake bands surrounding the brake drum and superimposed one upon the other, the ends of the inner band being disposed on the opposite side of the drum to those of the outer band, a link pivoted at one end to one end of the inner band and at its other end secured to the gear box, a pull rod secured to one end. of the outer band, a finger secured at one end to the gear box and at its other end pivotally supporting the said pull rod, a toggle lever pivotally connected to the said finger and engaging the free end of the outer band, astrut pivotally connected to the said toggle lever and a rocking bus bar supporting the said strut.

EDWARD WILSON. 

